[jfx11u] RFR: 8295659: Change JavaFX release version to 11.0.18 in jfx11u

[Johan Vos]

update javaFX release version to 11.0.18
Fix for JDK-8295659

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Commit messages:
 - update javaFX release version to 11.0.18

Changes: https://git.openjdk.org/jfx11u/pull/114/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx11u&pr=114&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295659
  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jfx11u/pull/114.diff
  Fetch: git fetch https://git.openjdk.org/jfx11u pull/114/head:pull/114

PR: https://git.openjdk.org/jfx11u/pull/114